Portion of a refrigerator display case



FIG. 1 is a perspective view of a portion of a refrigerator display case embodying my new design;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a side view of FIG. 1; and,

FIG. 4 is an enlarged top view of FIG. 1.

The broken line showing of the environment is for illustrative purposes only and forms no part of the claimed design. The broken lines which define the boundaries of the claimed design form no part thereof. 

The ornamental design for a portion of a refrigerator display case, as shown and described. 